Dosing and uses of Nebcin injection (tobramycin)
Adult dosage forms and strengths
injectable solution
- 10mg/mL
- 40mg/mL
Bacterial Infections
3-6 mg/kg/day IV/IM divided q8hr Or
4-7 mg/kg/dose IV/IM qDay
Renal Impairment
Clcr >60 mL/min: q8hr
Clcr 40-60 mL/min: q12hr
Clcr 20-40 mL/min: q24hr
Clcr 10-20 mL/min: q48hr
Clcr <10 mL/min: q72hr
Following dialysis in ESRd
Monitor
Peak and trough concentrations, renal and auditory function
Life-threatening infection: 8-10 mcg/mL
Serious infection: 6-8 mcg/mL
UTIs: 4-6 mcg/mL
Synergy for infections caused by gram-positive organisms: 3-5 mcg/mL
Other Indications & Uses
May have increase activity against resistant Gram negatives
Citrobacter spp., E. coli, P. aeruginosa, Proteus spp. (indole-positive and negative), Providencia spp. (including Klebsiella-Enterobacter-Serratia), S. aureus (coagulase-positive and negative)
Pediatric dosage forms and strengths
injectable solution
- 10mg/mL
- 40mg/mL
Cystic Fibrosis
IV/IM: 2.5-3.3 mg/kg q6-8hr
Neonates
<30 week gestation
- <28 days old: 2.5 mg/kg IV/IM qDay
- ≥28 days old: 3 mg/kg IV/IM qDay
30-36 week gestation
- <14 days old: 3 mg/kg IV/IM qDay
- ≥14 days old: 5 mg/kg/day IV/IM divided q12hr
>37 week gestation
- <7 days old: 5 mg/kg/day IV/IM divided q12hr
- ≥7 days old: 7.5 mg/kg/day IV/IM divided q8hr
Bacterial Infection
<5 years old: 2.5 mg/kg/dose IV/IM q8hr
≥5 years old: 2-2.5 mg/kg/dose IV/IM q8hr
Hemodialysis: 1.25-1.75 mg/kg/dose postdialysis
Monitor
Peak and trough concentrations, renal and auditory function
Life-threatening infection: 8-10 mcg/mL
Serious infection: 6-8 mcg/mL
UTIs: 4-6 mcg/mL
Synergy for infections caused by gram-positive organisms: 3-5 mcg/mL
Nebcin injection (tobramycin) adverse (side) effects
1-10%
Ototoxicity
Nephrotoxicity
Neurotoxicity (neuromuscular blockade)
<1%
Hypotension
Drug fever
Drowsiness
Headache
Paresthesia
Tremor
Rash
Nausea
Vomiting
Anemia
Eosinophilia
Arthralgia
Weakness
Eyelid edema
Itching eyes
Keratitis
Lacrimation
Dyspnea
Warnings
Black box warnings
Neurotoxicity, manifested as both bilateral auditory and vestibular ototoxicity, can occur in patients with preexisting renal damage and in patients with normal renal function treated at higher doses and/or for periods longer than those recommended. High-frequency deafness usually occurs first and can be detected only by audiometric testing. Vertigo may occur and may be evidence of vestibular injury
Aminoglycosides are potentially nephrotoxic. Risk is greater in patients with impaired renal function and in those who receive high doses or prolonged therapy. Rarely, nephrotoxicity may not become apparent until the first few days after cessation of therapy
Use with caution in premature infants and neonates because of renal immaturity and the resulting prolongation of serum half-life of the drug
Neuromuscular blockade and respiratory paralysis have been reported following parenteral injection, topical instillation (as in orthopedic and abdominal irrigation or in local treatment of empyema), and oral use of aminoglycosides, especially when given soon after anesthesia or muscle relaxants. If blockage occurs, calcium salts may reverse these phenomena, but mechanical respiratory assistance may be necessary
Avoid concurrent or sequential use of neurotoxic and/or nephrotoxic drugs including other aminoglycosides (eg, amikacin, streptomycin, neomycin, kanamycin, gentamicin, paromomycin
Cumulative listing of drugs to avoid from all aminoglycoside package inserts includes amphotericin B, bacitracin, cephaloridine, cisplatin, colistin, polymyxin B, vancomycin, and viomycin. Avoid potent diuretics (eg, ethacrynic acid, furosemide) because they increase risk of ototoxicity. When administered intravenously, diuretics may enhance aminoglycoside toxicity by altering antibiotic concentrations in serum and tissue
Contraindications
Documented hypersensitivity
Cautions
Concurrency with neuromuscular blockers
Aminoglycosides are associated with nephrotoxicity and ototoxicity
Renal impairment
Auditory or vestibular impairment
May cause irreversible hearing loss
Pregnancy and lactation
Pregnancy category: C
Lactation: enters breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Nebcin injection (tobramycin)
Mechanism of action
Inhibits protein synthesis by irreversibly binding to bacterial 30S and 50S ribosomes
Absorption
Absorption: IM: rapid and complete
Peak Plasma Time: IM: 30-60 min; IV: ~30 min
Distribution
Distribution: to extracellular fluid including serum, abscesses, ascitic, pericardial, pleural, synovial, lymphatic, and peritoneal fluids; crosses placenta; poor penetration into CSF, eye, bone, prostate
Protein Bound: <30%
Vd: 0.2-0.3 L/kg; pediatrics: 0.2-0.7 L/kg
Elimination
Half-Life: 2-3 hr (normal renal function)
Excretion: ~90%-95% in urine within 24 hr (normal renal function)
Administration
IV Incompatibilities
Additive: cefamandole, cefepime, cefotaxime, cefotetan, floxacillin, heparin, penicillins
Syringe: cefamandole, clindamycin, heparin
Y-site: allopurinol, amphotericin B cholesteryl sulfate, cefoperazone, heparin, hetastarch, indomethacin, propofol, sargramostim
IV Preparation
Standard diluent: 50-100 mL of D5W or Ns
IV Administration
Infuse over 30-60 min
Give penicillins or cephalosporins at least 1 hr apart from tobramycin
Storage
Stable at room temp both as the clear, colorless solution & as the dry powder
